USB-8451 OEM Specifications

SPECIFICATIONS
USB-8451 OEM
This user guide describes how to use the National Instruments USB-8451
OEM I2C/SPI communication device.
The NI USB-8451 OEM is a full-speed USB 2.0 device that provides I2C
and SPI connectivity with eight SPI chip selects and eight general-purpose
DIO channels.
Dimensional Drawings
Figure 1 shows a top view of the USB-8451 OEM. Figure 2 shows the front
and rear dimensions.
0.45 in. (11.5 mm)
0.18 in. (4.5 mm)
–0.03 in. (–0.8 mm)
–0.18 in. (–4.6 mm)
2.26 in. (57.4 mm)
1.78 in. (45.2 mm)
1.61 in. (40.8 mm)
1.45 in. (36.7 mm)
1.37 in. (34.7 mm)
0.89 in. (22.7 mm)
0.125 in. (3.18 mm) Diameter
2.13 in. (54.1 mm)
1.13 in. (28.7 mm)
0.48 in. (12.2 mm)
0.00 in. (0.0 mm)
0.00 in. (0.0 mm)
0.33 in. (8.3 mm)
0.13 in. (3.3 mm)
2.65 in. (67.3 mm)
2.41 in. (61.2 mm)
2.04 in. (51.8 mm)
1.66 in. (42.2 mm)
Figure 1. USB-8451 OEM Dimensions (Top View)
Pin 1
0.45 in. (11.5 mm)
0.25 in. (6.4 mm)
0.34 in. (8.6 mm)
0.06 in. (1.6 mm)
Figure 2. USB-8451 OEM Dimensions (Front and Rear Views)
Block Diagram
Figure 3 shows key functional components of the USB-8451 OEM.
VBus
I2C
USB Microcontroller
USB
SPI
Terminal Block
Full-Speed USB Interface
Short Circuit Protection
Current Limiting Circuit
P0.<0..7>
Figure 3. Device Block Diagram
Refer to the Safety Guidelines section of this document for important safety
information.
Installing Software and Hardware
Install the software provided with the USB-8451 OEM. Install the USB
device and cables. Refer to the NI-845x Software and Hardware
Installation Guide for more information.
USB-8451 OEM Specifications
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I/O Connector and Cable
Use any 34-pin female IDC (ribbon) cable to connect to the IDC connector
on the USB-8451 OEM.
Table 1 lists the pin assignments and signal names for the IDC connector.
Table 1. Pin Assignments
Signal
Pin
NC
Pin
Signal
1
2
GND
NC
3
4
SCLK
SDA
5
6
GND
SCL
7
8
MISO
NC
9
10
GND
CS5
11
12
MOSI
CS6
13
14
GND
CS7
15
16
CS0
P0.0
17
18
GND
P0.1
19
20
CS1
P0.2
21
22
GND
P0.3
23
24
CS2
P0.4
25
26
GND
P0.5
27
28
CS3
P0.6
29
30
GND
P0.7
31
32
CS4
+5V
33
34
+5V
© National Instruments Corporation
Connector
Pin 1
Pin 2
Pin 33
Pin 34
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USB-8451 OEM Specifications
Signal Descriptions
Table 2 describes the signals available on the I/O connectors.
Table 2. Signal Descriptions
Signal Name
Direction
Description
SPI CS <0..7>
Output
Chip Select Signals—Outputs used to select the desired
SPI peripheral device.
SPI MOSI (SDO)
Output
Master Output Slave Input—SPI communication
signal to slave device.
SPI MISO (SDI)
Input
Master Input Slave Output—SPI communication
signal from slave device.
SPI CLK (SCLK)
Output
SPI Clock—SPI output clock signal to slave devices
capable of clock rates up to 12 MHz.
I2C SDA
Input or
Output
I2C Serial Data—Data signal for I2C communication.
I2C SCL
Output
I2C Clock—I2C clock signal to slave devices capable of
clock rates up to 250 kHz.
P0.<0..7>
Input or
Output
Digital I/O Signals—You can individually configure
each signal as an input or output. You can configure the
port for open-drain or push-pull output.*
+5 V
Output
+5 V—The voltage source provided by the USB host.
The voltage is nominally 5 V, but varies from system to
system.
GND
—
Ground—The reference for the digital signals and the
+5 VDC supply.
NC
—
No Connect—Do not connect any signals to this
terminal.
* If you configure the DIO port for open-drain output, you must supply pull-up resistors to Vcc (3.3 or 5 V). The resistor
value must not be lower than 1 kΩ .
USB-8451 OEM Specifications
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Digital I/O
The USB-8451 OEM has eight single-ended digital lines, P0.<0..7>.
Static DIO
Each USB-8451 OEM DIO line can be individually programmed as a static
DI or DO line. You can use static DIO lines to monitor or control digital
signals. All samples of static DI lines and updates of DO lines are software
timed.
Digital Output Information
The default configuration of the USB-8451 OEM DIO port is push-pull,
allowing 3.3 V operation. You can add an external pull-up resistor (Rp) to
achieve 5 V operation, as shown in Figure 4. Do not use a pull-up resistor
of less than 1 kΩ.
USB-8451 DIO Box
Short Circuit Protection
Current Limiting Circuit
+5 V
VBus
P0.0
Port Pad
Rp
External
Pull-Up
Resistor
Rl
Load
A
GND
Figure 4. Example of Connecting External User-Provided Resistor
© National Instruments Corporation
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USB-8451 OEM Specifications
Digital I/O Circuitry
Figure 5 shows P0.<0..7> connected to example signals configured as
digital inputs and digital outputs. Refer to Figure 5 for some common
examples of connections of DIO lines with standard circuits.
+5 V
1
LED
P0.0
P0.1
P0.2
P0.3
P0.4
P0.5
P0.6
P0.7
2
+5 V
TTL Signal
3
Switch
GND
I/O Connector
1
2
3
P0.0 configured as an open-drain digital output driving a LED
P0.4 configured as a digital input receiving a TTL signal from a gated invertor
P0.7 configured as a digital input receiving a 0 V or 5 V signal from a switch
Figure 5. Example of Connecting a Load
Exceeding the maximum input voltage ratings or maximum output ratings, which
are listed in the Specifications section, can damage the USB device and the computer.
National Instruments is not liable for any damage resulting from such signal connections.
Caution
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SPI Circuitry
Figure 6 shows a typical SPI interface to three peripherals. All devices
share the SPI MISO, SPI MOSI, and SPI CLK signals. Each peripheral has
its own CS signal for addressing it.
USB-8451
CS 0
CS 1
Slave 0
CS 2
CS 3
CS 4
CS
MISO
CS 5
CS 6
CS 7
MOSI
CLK
Slave 1
SPI MOSI
(SDO)
CS
SPI MISO
(SDI)
MISO
MOSI
CLK
SPI CLK
(SCLK)
Slave 2
GND
CS
MISO
MOSI
CLK
Figure 6. SPI Interface to Three Peripherals
© National Instruments Corporation
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USB-8451 OEM Specifications
I2C Circuitry
Figure 7 shows a typical I2C interface to two peripherals. All devices on the
I2C bus share the SDA and SCL signals. SDA and SCL must be pulled up
externally. Refer to the I2C specification to select the correct resistor values
for your bus.
VDD
VDD
USB-8451
SDA
Slave 0
SCL
SDA
SCL
GND
GND
Slave 1
SDA
SCL
GND
Figure 7. I2C Interface to Two Peripherals
I/O Protection
Each DIO, SPI, and SPI CS signal is protected against overvoltage,
undervoltage, and overcurrent conditions, as well as ESD events. However,
you should avoid these fault conditions by using the following guidelines:
USB-8451 OEM Specifications
•
If you configure a line as an output, do not connect it to any external
signal source, ground signal, or power supply.
•
If you configure a line as an output, understand the current
requirements of the load connected to these signals. Do not exceed the
specified current output limits of the USB-8451 OEM.
•
If you configure a line as an input, do not drive the line with voltages
outside of its normal operating range.
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•
Treat the USB-8451 OEM as you would treat any static sensitive
device. Always properly ground yourself and the equipment when
handling the USB device or connecting to it.
Take special care with respect to the I2C SDA and SCL lines. To allow for external
pull-ups, the circuit protection has been removed. Do not exceed the specified voltages for
these signals.
Caution
Power-On States
At system startup and reset, the hardware sets all DIO lines to
high-impedance inputs. The USB-8451 OEM does not drive the signal high
or low.
+5 V Power Source
The USB-8451 OEM supplies a nominal 5 V from two pins, one on each
screw terminal block. The voltage source is provided by the USB host. The
voltage is nominally 5 V, but varies from system to system. Refer to the
Specifications section for more information about USB bus power
specifications. This source can be used to power external components.
Note
While the device is in USB suspend, the output is disabled.
When using the 5 V source, understand the current requirements of the load
connected. Do not exceed the specified current output limits of the USB Vbus.
Caution
Specifications
The following specifications are typical at 25 °C, unless otherwise noted.
Digital I/O and Chip Selects
Number of lines
P0.<0..7>......................................... 8
CS <0..7> ........................................ 8
Direction control .................................... Input or output,
software selectable
Output driver type .................................. Push-pull (active drive) or
open-drain (DIO only),
software selectable
© National Instruments Corporation
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USB-8451 OEM Specifications
Absolute voltage range ...........................–0.5 to 5.8 V with respect to GND
Power-on state ........................................Input (high impedance)
Digital logic levels
Level
Input
Input low voltage
Input high voltage
Input leakage current
Output
Output low voltage (I = 8.5 mA)
Output high voltage
Push-pull (active drive), I = –8.5 mA
Open-drain (DIO only)
Min
Max
Units
–0.3
2.0
—
0.8
5.8
50
V
V
µA
—
0.8
V
2.0
Vcc*
3.5
Vcc*
V
V
* Vcc refers to the pull-up voltage you select.
SPI Interface
Signals
SPI MOSI (SDO).............................Output
SPI MISO (SDI) ..............................Input
SPI CLK (SCLK) ............................Output (12 MHz max)
Supported clock rates..............................48 kHz, 50 kHz, 60 kHz, 75 kHz,
80 kHz, 96 kHz, 100 kHz,
120 kHz, 125 kHz, 150 kHz,
160 kHz, 200 kHz, 240 kHz,
250 kHz, 300 kHz, 375 kHz,
400 kHz, 480 kHz, 500 kHz,
600 kHz, 750 kHz, 800 kHz,
1 MHz, 1.2 MHz, 1.5 MHz,
2 MHz, 2.4 MHz, 3 MHz, 4 MHz,
6 MHz, 12 MHz
Output driver type...................................Push-pull (active drive)
Absolute voltage range ...........................–0.5 to 5.8 V with respect to GND
Power-on state ........................................Input (high impedance)
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Digital logic levels
Level
Input
Input low voltage
Input high voltage
Input leakage current
Output
Output low voltage (I = 8.5 mA)
Output high voltage
Push-pull (active drive), I = –8.5 mA
Min
Max
Units
–0.3
2.0
—
0.8
5.8
50
V
V
µA
—
0.8
V
2.0
3.5
V
I2C Interface
Signals
SDA ................................................ Output/Input
SCL ................................................. Output (250 kHz max)
Supported clock rates ............................. 32 kHz, 40 kHz, 50 kHz, 64 kHz,
80 kHz, 100 kHz, 125 kHz,
160 kHz, 200 kHz, 250 kHz
Output driver type .................................. Open-drain
Absolute voltage range........................... –0.5 to 5.8 V with respect to GND
Power-on state........................................ Input (high impedance)
Digital logic levels
Level
Output
Output low voltage (I = 8.5 mA)
Output high voltage
Open-drain with external pull-up resistor
Note
Min
Max
Units
—
0.8
V
2.0
—
V
This interface is compatible with both I2C and SMBus devices.
Bus Interface
USB specification .................................. Full-speed (12 Mb/s)
© National Instruments Corporation
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USB-8451 OEM Specifications
External Voltage
+5 V output
Voltage ............................................4.10 V min, 5.25 V max
Current.............................................230 mA max
Power Requirements
USB
4.10 to 5.25 VDC.............................80 mA typical, 500 mA max
USB Suspend...................................300 µA standby mode,
500 µA max
Physical Characteristics
Dimensions
Without connectors..........................6.35 cm × 8.51 cm × 2.31 cm
(2.50 in. × 3.35 in. × 0.91 in.)
With connectors...............................8.18 cm × 8.51 cm × 2.31 cm
(3.22 in. × 3.35 in. × 0.91 in.)
I/O connectors.........................................USB series B receptacle,
(2) 16 position (screw terminal)
plug headers
Screw-terminal wiring ............................16 AWG to 28 AWG copper
conductor wire with 10 mm
(0.39 in.) of insulation stripped
from the end
Torque for screw terminals.....................0.22 to 0.25 N · m
(2.0 to 2.2 lb · in.)
Weight ....................................................84 g (3 oz)
Safety
Standards
The USB-8451 OEM is designed to meet the requirements of the following
standards of safety for electrical equipment for measurement, control,
and laboratory use:
USB-8451 OEM Specifications
•
IEC 61010-1, EN 61010-1
•
UL 61010-1
•
CAN/CSA-C22.2 No. 61010-1
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Note For UL and other safety certifications, refer to the product label, or visit
ni.com/certification, search by model number or product line, and click the
appropriate link in the Certification column.
Overvoltage Protection
Connect only voltages that are within these limits.
Channel-to-COM (one channel)............. ± 30 V max,
Measurement Category I
Channels-to-COM
(one port, all channels)........................... ± 8.9 V max,
Measurement Category I
Measurement Category I is for measurements performed on circuits not
directly connected to the electrical distribution system referred to as
MAINS voltage. MAINS is a hazardous live electrical supply system that
powers equipment. This category is for measurements of voltages from
specially protected secondary circuits. Such voltage measurements include
signal levels, special equipment, limited-energy parts of equipment,
circuits powered by regulated low-voltage sources, and electronics.
Caution Do not use this module for connection to signals or for measurements within
Measurement Categories II, III, or IV.
Hazardous Locations
The USB-8451 OEM is not certified for use in hazardous locations.
Environmental
The USB-8451 OEM device is intended for indoor use only.
Operating temperature
(IEC 60068-2-1 and IEC 60068-2-2) ..... 0 to 45 °C
Operating humidity
(IEC 60068-2-56) ................................... 10 to 90% RH, noncondensing
Maximum altitude .................................. 2,000 m (at 25°C ambient
temperature)
Storage temperature
(IEC 60068-2-1 and IEC 60068-2-2) ..... –40 to 85 °C
© National Instruments Corporation
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USB-8451 OEM Specifications
Storage humidity
(IEC 60068-2-56) ..................................5 to 90% RH, noncondensing
Pollution Degree (IEC 60664) ................2
Electromagnetic Compatibility
Emissions................................................EN 55011 Class A at 10 m
FCC Part 15A above 1 GHz
Immunity ................................................Industrial levels per
EN 61326:1997 + A2:2001,
Table 1
EMC/EMI ...............................................CE, C-Tick, and FCC Part 15
(Class A) Compliant
Note
For EMC compliance, operate this device with shielded cabling.
CE Compliance
This product meets the essential requirements of applicable European
Directives, as amended for CE marking, as follows:
Low-Voltage Directive (safety)..............73/23/EEC
Electromagnetic Compatibility
Directive (EMC) .....................................89/336/EEC
Refer to the Declaration of Conformity (DoC) for this product for any additional
regulatory compliance information. To obtain the DoC for this product, visit
ni.com/certification, search by model number or product line, and click the
appropriate link in the Certification column.
Note
USB-8451 OEM Specifications
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Safety Guidelines
Caution
Operate the hardware only as described in these operating instructions.
The following section contains important safety information that you must
follow when installing and using the USB-8451 OEM.
Do not operate the USB-8451 OEM in a manner not specified in this
document. Misuse of the device can result in a hazard. You can compromise
the safety protection built into the device if the device is damaged in any
way. If the device is damaged, contact National Instruments for repair.
Do not substitute parts or modify the device except as described in this
document. Use the device only with the chassis, modules, accessories, and
cables specified in the installation instructions. You must have all covers
and filler panels installed during operation of the device.
Do not operate the device in an explosive atmosphere or where there may
be flammable gases or fumes. If you must operate the device in such an
environment, it must be in a suitably rated enclosure.
If you need to clean the device, use a dry cloth. Make sure that the device
is completely dry and free from contaminants before returning it to service.
Operate the device only at or below Pollution Degree 2. Pollution is foreign
matter in a solid, liquid, or gaseous state that can reduce dielectric strength
or surface resistivity. The following is a description of pollution degrees:
•
Pollution Degree 1 means no pollution or only dry, nonconductive
pollution occurs. The pollution has no influence.
•
Pollution Degree 2 means that only nonconductive pollution occurs in
most cases. Occasionally, however, a temporary conductivity caused
by condensation must be expected.
•
Pollution Degree 3 means that conductive pollution occurs, or dry,
nonconductive pollution occurs that becomes conductive due to
condensation.
You must insulate signal connections for the maximum voltage for which
the device is rated. Do not exceed the maximum ratings for the device. Do
not install wiring while the device is live with electrical signals. Do not
remove or add connector blocks when power is connected to the system.
Avoid contact between your body and the connector block signal when hot
swapping modules. Remove power from signal lines before connecting
them to or disconnecting them from the device.
© National Instruments Corporation
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USB-8451 OEM Specifications
Operate the device at or below the Measurement Category I1. Measurement
circuits are subjected to working voltages2 and transient stresses
(overvoltage) from the circuit to which they are connected during
measurement or test. Measurement categories establish standard impulse
withstand voltage levels that commonly occur in electrical distribution
systems. The following is a description of measurement categories:
•
Measurement Category I is for measurements performed on circuits
not directly connected to the electrical distribution system referred to
as MAINS3 voltage. This category is for measurements of voltages
from specially protected secondary circuits. Such voltage
measurements include signal levels, special equipment, limited-energy
parts of equipment, circuits powered by regulated low-voltage sources,
and electronics.
•
Measurement Category II is for measurements performed on circuits
directly connected to the electrical distribution system. This category
refers to local-level electrical distribution, such as that provided by a
standard wall outlet (for example, 115 V for U.S. or 230 V for Europe).
Examples of Measurement Category II are measurements performed
on household appliances, portable tools, and similar E Series devices.
•
Measurement Category III is for measurements performed in the
building installation at the distribution level. This category refers to
measurements on hard-wired equipment such as equipment in fixed
installations, distribution boards, and circuit breakers. Other examples
are wiring, including cables, bus-bars, junction boxes, switches,
socket-outlets in the fixed installation, and stationary motors with
permanent connections to fixed installations.
Measurement Category IV is for measurements performed at the primary
electrical supply installation (<1,000 V). Examples include electricity
meters and measurements on primary overcurrent protection devices and
on ripple control units.
1
2
3
Measurement Category as defined in electrical safety standard IEC 61010-1. Measurement Category is also referred to as
Installation Category.
Working Voltage is the highest rms value of an AC or DC voltage that can occur across any particular insulation.
MAINS is defined as a hazardous live electrical supply system that powers equipment. Suitably rated measuring circuits may
be connected to the MAINS for measuring purposes.
USB-8451 OEM Specifications
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Where to Go for Support
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for your product by visiting ni.com/certification. If your product
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290598A-01
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